Abstract: This invention relates to a composition, comprising: an unsaturated functionalized monomer of from about 5 to about 30 carbon atoms, which is: (a) polymerized to form a functionalized polymer; (b) copolymerized with a comonomer to form a functionalized copolymer; or (c) reacted with an enophilic reagent to form a polyfunctionalized monomer. The polyfunctionalized monomer may be polymerized to form a polyfunctionalized polymer which may be further reacted with one or more additional reagents. The invention relates to lubricants, functional fluids, fuels, dispersants, detergents and polymeric resins.

Abstract: A lubricant composition having improved non-Newtonian viscometrics includes at least 85 weight percent of a base oil and 1 to 15 weight percent of a lubricant additive. The additive itself includes 10 to 80 weight percent of a diluent oil and 30 to 80 weight percent of a random co-polymeric viscosity index improver. The viscosity index improver is the free-radical polymerization product of at least 5 to 15 weight percent methyl methacrylate and 5 to 95 weight percent of a C8-C10 alkyl (meth)acrylate. The additive is formed using a method that includes the step of providing the diluent oil, the methyl methacrylate, the C8-C10 alkyl (meth)acrylate, and a free-radical initiator. The method also includes the steps of flowing the diluent oil into a reactor, flowing the methyl methacrylate and the C8-C10 alkyl (meth)acrylate into the reactor independently from the free-radical initiator, and flowing the free-radical initiator into the reactor.

Abstract: The present invention relates to carboxyl-containing polymers having higher storage stability and improved processability in the form of powders, pellets or granules and to their use in laundry detergents and cleaners, and also in further fields of use.

Abstract: The present invention relates to a lubricating composition containing an oil of lubricating viscosity and a star polymer that has at least two inner blocks, at least one of which is in turn bonded to one or more outer blocks. The invention further relates to methods of lubricating a mechanical device with the lubricating composition.

Abstract: The disclosure provides a lubricating oil composition and method for manufacturing the same. The lubricating oil composition substantially consists of a base lubricant oil, and an organic-inorganic composite particle uniformly dispersed in the base lubricant oil. This lubricating oil composition is applicable to a sliding section or sliding member of an automotive internal combustion engine or power transmission apparatus to significantly reduce friction coefficient, temperature of oil and wear rate.

Abstract: A base oil for hydraulic oil suitably used for hydraulic systems having filters of which micropore diameter is 50 ?m or less is disclosed. The disclosure also provides a hydraulic oil composition using the above base oil, especially a hydraulic oil composition suitably used for such as tractors, transmissions, and common systems thereof having the hydraulic systems. The base oil has mineral oil, and the mineral oil is defined by kinematic viscosity at 100° C.: 1.5˜6 mm2/s, pour-point: ?10° C. or less, viscosity index: 100 or more, % CP: 70 or more, % CA: 2 or less, and aniline point: 106° C. or more, and the mineral base oil is treated by catalytic dewaxing process and/or contains tertiary carbon atoms at a ratio of 7.4% or more to the total carbon atoms.

Abstract: The present invention relates to the use of a branched addition copolymer in combination with a polymer in a solution or melt formulation to reduce the viscosity of the solution formulation and/or melt formulation compared to the viscosity of a solution and/or melt comprising the polymer alone wherein the branched addition copolymer is obtainable by an addition polymerisation process, methods for the preparation of the formulations, and novel branched addition copolymers for use as same.

Abstract: The lubricating oil composition of the invention includes a lubricating base oil with a kinematic viscosity at 100° C. of 1-6 mm2/s, a % Cp of 70 or greater and a % CA of no greater than 2, and a viscosity index improver which, when added to the lubricating base oil, results in an A/B ratio of less than 3.2 and a C/B ratio of less than 1.5. A is the thickening effect on the kinematic viscosity at 100° C., B is the thickening effect on the HTHS viscosity at 150° C., and C is the thickening effect on the HTHS viscosity at 100° C.

Abstract: The present invention relates to the use of branched addition copolymers possessing melt or solution viscosities lower than the linear polymer analogues of equivalent or greater weight average molecular weight, compositions comprising said copolymers, methods for their preparation, and he use of novel polymers per se in for example but not limited to solution formulations or melt formulations.

Abstract: The present invention provides a lubricating composition comprising a base oil (A) and a hydroxyl group-added poly(meth)acrylate (B).

Abstract: The lubricating oil composition of the invention comprises a lubricating base oil with a kinematic viscosity at 100° C. of 1-20 mm2/s, and a viscosity index improver having a ratio M1/M2 of 0.20 or greater, between the total area of the peaks between chemical shifts of 36-38 ppm M1 and the total area of the peaks between chemical shifts of 64-66 ppm M2, with respect to the total area of all of the peaks, in the spectrum obtained by 13C-NMR. The lubricating oil composition of the invention has excellent effects, with a sufficiently high HTHS viscosity at 150° C., and a sufficiently low kinematic viscosity at 40° C., a sufficiently low kinematic viscosity at 100° C. and a sufficiently low HTHS viscosity at 100° C.

Abstract: A lubricant composition suitable for lubricating an internal combustion engine comprises: (a) an oil of lubricating viscosity having a viscosity index of at least 105 and a kinematic viscosity at 100 C of less than 7 mm2s-1; (b) 0.01 to 2 weight percent of a friction modifier represented by the structure [I]; (c) 0.5 to 4 weight percent of a poly(meth)acrylate viscosity modifier polymer; (d) 0 to 500 parts per million by weight of molybdenum in the form of an oil-soluble molybdenum compound; and (e) 0 to 200 parts per million by weight of boron in the form of an oil-soluble boron compound.

Abstract: A lubricating composition contains an oil of lubricating viscosity and 0.5 to 10 percent by weight of a poly (meth)acrylate viscosity modifier polymer comprising (i) 15 weight percent to 35 weight percent monomer units of methyl (meth) acrylate, (ii) 0 to 10 weight percent monomer units of one or more C2-C6 alkyl (meth)acrylates, (iii) 50 to 85 weight percent monomer units of one or more C8-C30 alkyl (meth)acrylates, and (iv) 0 to 10 weight percent monomer units of one or more nitrogen-containing monomers. Such a lubricating composition exhibits a high viscosity index and may impart improved fuel economy to an internal combustion engine.

Abstract: This invention discloses a lubricant suitable for use in percussion equipment. The lubricant comprises a base oil selected from the group consisting of Group I or Group II, blended in a synergistic amount with a gear oil package and a friction modifier. The lubricant exhibits superior wear and superior extreme pressure properties due to the synergistic effect of the gear oil package and the friction modifier. In a preferred embodiment, the gear oil package comprises a polyalkyl methacrylate polymer, and the friction modifier comprises a synthetic ester.

Abstract: The present invention relates to compositions and methods for improving the melt processing of polymeric materials, and more particularly to the use of compatibilized polymer processing additives to enhance the melt processing of polymeric matrices.

Abstract: This invention provides an oil composition for cutting and grinding by minimum quantity lubrication system, characterized by comprising an ester oil with a kinematic viscosity of 0.5-20 mm2/s at 100° C., and an ester-based polymer with a kinematic viscosity exceeding 20 mm2/s at 100° C. and an average molecular weight of 5,000-10,000,000. The oil composition for cutting and grinding by minimum quantity lubrication system according to the invention can achieve an excellent balance between misting property and inhibition of floating mist and ensure that an adequate amount reaches the working section, for cutting and grinding by minimum quantity lubrication system.

Abstract: The present invention relates to a branched copolymer comprising a hydrophilic component obtainable by an addition polymerisation process and compositions and uses thereof said copolymer comprising: i) a residue of at least one monofunctional monomer comprising one polymerisable double bond per molecule and a molecular weight of less than 1000 Daltons; ii) a residue of at least one multifunctional monomer comprising at least two polymerisable double bonds per molecule and a molecular weight of less than 1000 Daltons; and wherein the end termini of the copolymer chains comprise one or more of a residue of a chain transfer agent; an initiator or a terminal group derived from a termination reaction; wherein; the molar ratio of the monofunctional monomer to multifunctional monomer is between 50:1 to 2.

Abstract: The present invention generally relates to a method for reducing intake valve deposits in a Direct Injection Spark Ignition engine, the method comprising operating the engine with a lubricating oil composition comprising: (a) a major amount of an oil of lubricating viscosity; and (b) at least one foam inhibitor selected from the group consisting of silicon oils, polysiloxanes, polyacrylates, and polymethacrylates; wherein the foam inhibitor is not poly (phenyl-methyl) siloxane; and further wherein the amount of said foam inhibitor in said lubricating oil composition is at an effective concentration to achieve at least 10% reduction in intake valve deposits in said Direct Injection Spark Ignition engine compared to operating the engine with said lubricating oil composition without any foam inhibitor.

Abstract: (EN) The invention relates to a polymer comprising 50-100% by weight, with regard to the weight of the polymers, of repeating units, which are derived from one or more ethylenically unsaturated ester compounds of formula (I), in which R represents hydrogen or methyl; R1 represents a linear or unbranched alkyl radical with 7 to 30 carbon atoms, and; R2 and R3 independently represent hydrogen or a group of formula —COOR?, wherein R? represents hydrogen or an alkyl group with 7 to 30 carbon atoms. The polymer is a star polymer with 3 to 21 arms and at least 3 of the arms consist of at least 40% by weight, with regard to the weight of the arms, of repeating units, which are derived from one or more ethylenically unsaturated ester compounds of formula (I), in which R1 represents a linear or unbranched alkyl radical with 7 to 30 carbon atoms, and; R2 and R3 independently represent hydrogen or a group of formula —COOR?, wherein R? represents hydrogen or an alkyl group with 7 to 30 carbon atoms.

Abstract: There is provided a pour point depressant for lubricants that has an effect of lowering pour points of both solvent refined base oils and high viscosity index base oils. A pour point depressant for lubricants comprising: a mixture of an alkyl (meth)acrylate polymer (A) that is composed of an alkyl(meth)acrylate containing alkyl groups having an average carbon number (CA) of 12.5 to 13.8, and an alkyl(meth)acrylate polymer (B) that is composed of an alkyl(meth)acrylate containing alkyl groups having an average carbon number (CB) of 13.9 to 15.5.

Abstract: Poly methacrylate copolymers are disclosed which comprising from about 60 to about 96 weight percent of a C12-C16 alkyl methacrylate and from about 40 to about 4 weight percent of a C18-C30 alkyl methacrylate and provide excellent low temperature properties to lubricating oils.

Abstract: The invention provides a lubricating oil composition comprising a lubricating base oil with a kinematic viscosity at 100° C. of 1-10 mm2/s, a % Cp; of 70 or greater and a % CA of no greater than 2 and a viscosity index improver having a weight-average molecular weight of 100,000 or greater and a ratio of weight-average molecular weight to PSSI of 1.0×104 or greater, at 0.1-50% by mass based on the total amount of the composition, and having a kinematic viscosity at 100° C. of 9.0-12.5 mm2/s and a HTHS viscosity at 150° C. of 2.8 mPa·s or greater. It further provides a lubricating oil composition comprising a lubricating base oil with a kinematic viscosity at 100° C. of 1-6 mm2/s, a % Cp of 70 or greater and a % CA of no greater than 2, a hydrocarbon-based viscosity index improver with a PSSI of no greater than 20, and a poly(meth)acrylate-based viscosity index improver.

Abstract: A lubricant oil composition comprising: a lubricant base oil whose kinematic viscosity at 100° C. is 1 to 6 mm2/s, % Cp is not less than 70, and % CA is not more than 2; a first viscosity index improver in which the ratio A/B of a viscosity increasing effect A in the equation (1) to a viscosity increasing effect B in the equation (2) when added to the lubricant base oil is a value of not less than 4.5, and a PSSI is not more than 30; and a second viscosity index improver in which the ratio A/B when added to the lubricant base oil is a value less than 4.5: A=X?X0 ??(1) B=Y?Y0 ??(2) wherein A represents a viscosity increasing effect of the kinematic viscosity at 100° C., B represents a viscosity increasing effect of the HTHS viscosity at 150° C., X represents a kinematic viscosity at 100° C. of a mixture of the lubricant base oil with 3% by mass of the first or second viscosity index improver, X0 represents a kinematic viscosity at 100° C.

Abstract: A lubricant oil composition according to the present invention comprises: a lubricant base oil whose kinematic viscosity at 100° C. is 1 to 20 mm2/s; and a viscosity index improver in which a ratio M1a/M2a of a total area M1a of peaks in a chemical shift between 29-31 ppm to a total area M2a of peaks in a chemical shift between 64-69 ppm based on a total area of all the peaks is not less than 10 in a spectrum obtained by 13C-NMR.

Abstract: Lubricating oil compositions for transmissions comprises (A) a lubricating base oil with a kinematic viscosity at 100° C. adjusted to 1.5 to 6 mm2/s, composed of (A1) a lubricating base oil with a kinematic viscosity at 100° C. of 1.5 mm2/s or higher and lower than 7 mm2/s or (A1) the lubricating oil and (A2) a lubricating base oil with a kinematic viscosity at 100° C. of 7 to 50 mm2/s, blended with (B) a poly(meth)acrylate-based additive, so that the composition has a kinematic viscosity at 100° C. of 3 to 8 mm2/s and a viscosity index of 95 to 200, (A) and (B) fulfill a specific requirement. The compositions achieve long fatigue life though having low viscosity.

Abstract: A lubricant which contains an ester oil and a polyalkyl(meth)acrylate copolymer having in copolymerized form a C1-C4 alkyl(meth)acrylate, and a C4-C4000 alkyl(meth)acrylate exhibits an improved Viscosity Index compared to a lubricant having no ester oil.

Abstract: The present invention relates to copolymers obtainable by polymerizing a monomer composition composed of a) 0% to 40% by weight of one or more ethylenically unsaturated ester compounds of the formula (I) in which R is hydrogen or methyl, R1 is a linear or branched alkyl radical having 1 to 5 carbon atoms, R2 and R3 independently are hydrogen or a group of the formula —COOR?, in which R1 is hydrogen or an alkyl group having 1 to 5 carbon atoms, b) 10% to 99.

Abstract: Copolymers are obtainable by polymerizing a monomer composition containing a) 0% to 40% by weight of one or more ethylenically unsaturated ester compounds of the formula (I), b) 10% to 99.9% by weight of one or more ethylenically unsaturated ester compounds of the formula (II), c) 0% to 80% by weight of one or more ethylenically unsaturated ester compounds of the formula (III), d) 0.1% to 30% by weight of one or more ethylenically unsaturated, polar ester compounds of the formula (IV), and e) 0% to 50% by weight of comonomer, based in each case on the total weight of the ethylenically unsaturated monomers.

Abstract: A lubricant composition comprising an oil of lubricating viscosity, an amino-functionalized acrylic or methacrylic-containing polymer, comprising about 2 percent to about 8 percent by weight of an amine moiety bearing a tertiary amino group, attached to said polymer through an ester, amide, or imide linkage; and a nitrogen-containing dispersant, provides reduced friction to an internal combustion engine and improved fuel economy.

Abstract: The present invention relates to a branched copolymer obtainable by an addition polymerisation process and uses and compositions thereof comprising a hydrophilic component, said polymer comprising: i) a residue of at least one monofunctional monomer comprising one polymerisable double bond per molecule and a molecular weight of less than 1000 Daltons; ii) a residue of at least one multifunctional monomer comprising at least two polymerisable double bonds per molecule and a molecular weight of less than 1000 Daltons; and wherein the end termini of the copolymer chains comprise one or more of a residue of a chain transfer agent; an initiator or a terminal group derived from a termination reaction; wherein; the molar ratio of the monofunctional monomer to multifunctional monomer is between 50:1 to 2.5:1 respectively; and wherein the hydrophilic component is comprised solely of at least 1 mole % of one or more monofunctional monomer which is/are comprised of hydrophilic monomer each with a solubility of 0.

Abstract: The invention provides a lubricating composition containing (a) 0.001 to 15 wt % of a polymer with (i) a weight average molecular weight of 50,000 to 1,000,000; and (ii) a shear stability index of 10 to 100; (b) an antiwear agent; (c) a corrosion inhibitor; and (d) an oil of lubricating viscosity. The invention further provides a method for lubricating a mechanical device with the lubricating composition.

Abstract: The invention relates to the use of comb polymers comprising repeating units in the main chain which repeating units are derived from polyolefin-based macromonomers having a molecular weight of at least 500 g/mol, and repeating units which are derived from low-molecular monomers having a molecular weight of less than 500 g/mol as antifatigue additives in lubricants. The invention further relates to novel comb polymers and methods for the production thereof and to lubricating oils comprising said comb polymers.

Abstract: The present invention provides a low ash engine oil composition which, despite the low ash content, has engine detergency which enables the composition to pass severe detergency tests for diesel engine oils. The engine oil composition contains 0.6 percent by mass or less of a sulfated ash and comprises a low ash engine oil composition with a sulfated ash content of 0.6 percent by mass or less, which comprises: a lubricating base oil with a % CA of 2 or less, a kinematic viscosity at 40° C. of 25 mm2/s or less and a viscosity index of 120 or greater; a viscosity index improver contained in such an amount that the viscosity index of the composition will be 160 or greater; (A) a metallic detergent with a metal ratio of 3 or less; and/or (B) a sulfur-free phosphorus compound.

Abstract: The invention relates to comb polymers which comprise, in the main chain, repeating units which are derived from polyolefin-based macromonomers, and repeating units which are derived from low molecular monomers which are selected from the group consisting of styrene monomers having 8-17 carbon atoms, alkyl(meth)acrylates having 1-10 carbon atoms in the alcohol group, vinyl esters having 1-11 carbon atoms in the acyl group, vinyl ethers having 1-10 carbon atoms in the alcohol group, (Di)alkylfumarates having 1-10 carbon atoms in the alcohol group, (Di)alkylmaleates having 1-10 carbon atoms in the alcohol group and mixtures of said monomers. The molar branching degree lies in the region between 0.1-10 mol. % and the comb polymer represents the sum of at least 80 wt.

Abstract: An oil-soluble lubricating oil additive composition prepared by the process which comprises reacting a copolymer, with at least one ether compound, with at least one aliphatic compound, and with at least one aromatic compound.

Abstract: The present invention relates to methods of lubricating a mechanical device by using a low sulfur lubricating composition that contains a friction modifier and provides improved antiwear performance. The invention further provides the lubricating compositions used therein.

Abstract: A hydrocarbon-based lubricating base oil wherein a urea adduct value is not greater than 4% by mass, a viscosity index is 100 or higher, an average of carbon atoms number is 23-31 as determined by gas chromatography distillation, a value obtained by dividing an integral value of a peak in 30 ppm by an integral value of total peaks in the range of from 0 ppm to 50 ppm for the 13C-NMR spectrum is 0.1-0.2, and a product of a value obtained by dividing an integral value of peaks attributed to tertiary carbon atoms by an integral value of total peaks in the range of from 0 ppm to 50 ppm for the 13C-NMR spectrum, and the average of carbon atoms number, is 1.8-2.5.

Abstract: A functional fluid comprising a base oil with a high viscosity index, wherein the functional fluid has a kinematic viscosity at 100° C. between 2.5 and 5.0 mm2/s, a low Brookfield viscosity, a high aniline point, and excellent air release. Shock absorber fluids with improved performance, comprising a particular base oil, wherein the improved performance includes high viscosity index, low Brookfield viscosity, high aniline point, excellent air release and high flash point.

Abstract: The present invention is directed to a lubricating oil composition, a diesel engine comprising a lubricating oil composition, and a method of lubricating a diesel engine provided with an exhaust gas recirculation system, comprising lubricating said engine with a lubricating oil composition comprising an oil of lubricating viscosity, and a polymeric N-dispersant booster comprising monomer units of: a) 0 to 40 wt. % of one or more ethylenically unsaturated ester compounds of formula (I) wherein R is equal to H or CH3, R1 represents a linear or branched alkyl group with 1 to 5 carbon atoms, R2 and R3 independently represent H or a group of the formula —COOR?, wherein R? is H or an alkyl group with 1 to 5 carbon atoms, b) 10 to 98 wt.

Abstract: The present invention provides a lubricating composition comprising: (a) an oil of lubricating viscosity; and (b) a crosslinked polymer derived from monomers comprising: (i) 0.001 wt % to 7 wt % of a di- or higher functional crosslinking monomer; (ii) 30 wt % or higher of a hydrocarbyl-substituted (meth)acrylic monomer, wherein each hydrocarbyl contains greater than 8 carbon atoms; and (iii) 0 wt % to 40 wt % of a hydrocarbyl-substituted (meth)acrylic monomer, wherein each hydrocarbyl contains 8 or fewer carbon atoms. The invention further provides a method of preparing the crosslinked polymer and its use in a lubricating composition for lubricating an internal combustion engine.

Abstract: Mineral oil compositions with trace portions of additives contain as additive a comb polymer containing ester linkages, either based on a) ethylene-vinylester copolymers modified by hydroxy groups or glycidyl groups with molecular mass weight averages from 3000 to 50000 and an ethylene portion of 50 to 90 mass %, and b) partially imidated and/or partially esterified maleic anhydride copolymers, wherein in the comb polymer based on a) and b) the modified ethylene-vinylester copolymer component is connected by means of ester linkages to the partially imidated and/or partially esterified maleic anhydride copolymer component, or a comb polymer containing ester linkages based on c) ethylene-vinylester copolymers modified by acid and/or acid anhydride groups with molecular mass weight averages from 3000 to 50000 and an ethylene portion of 50 to 90 mass %, and d) polyalcohols partially esterified with C12-C40-monocarboxylic acids wherein in the comb polymer based on c) and d) the ethylene-vinylester copolymer c

Abstract: The present invention relates to an extra light hydrocarbon liquid derived from highly paraffinic wax. This extra light hydrocarbon liquid is suitable for use as a lubricant additive diluent oil in oil soluble additive concentrates. This extra light hydrocarbon liquid derived from highly paraffinic wax has a viscosity of between about 1.0 and 3.5 cSt at 100° C. and a Noack volatility of less than 50 weight % and comprises greater than 3 weight % molecules with cycloparaffinic functionality and less than 0.30 weight percent aromatics. The extra light hydrocarbon liquid makes an excellent lubricant additive diluent oil because it has low volatility, low viscosity, good additive solubility, and excellent solubility in lubricant base oil stocks. The present invention also relates to finished lubricants comprising the oil soluble additive concentrates made with the extra light hydrocarbon liquid and finished lubricants comprising the oil soluble additive concentrates.

Abstract: The present invention relates to the use of a polyalkylmethacrylate polymer to improve the air release of a functional fluid.

Abstract: An oil-soluble lubricating oil additive composition prepared by the process which comprises reacting a copolymer, with at least one ether compound and with at least one aromatic compound.

Abstract: The present invention relates to acrylic block copolymers synthesized by a controlled free-radical process, and their use as low temperature flow modifiers in oil-based compositions. They are especially useful in modifying the low temperature flow behavior in lubricating oils. The acrylic copolymers are especially useful as pour point depressants in lubricating oil.

Abstract: The invention provides a lubricating oil composition comprising: a lubricating base oil having a kinematic viscosity at 100° C. of 1-10 mm2/s, a % Cp of 70 or greater and a % CA of not greater than 2; a first viscosity index improver of 0.01-10% by mass, based on the total weight of the composition, wherein the first viscosity index improver is a poly(meth)acrylate having a weight-average molecular weight of not greater than 100,000; and a second viscosity index improver of 0.01-50% by mass, based on the total weight of the composition, wherein the second viscosity index improver is a polymer having a weight-average molecular weight of 100,000 or greater and containing a structural unit represented by the following formula (1) in a proportion of 0.5-70 mol %, the composition having a kinematic viscosity at 100° C. of 4-12 mm2/s and a viscosity index of 140-300.

Abstract: A method for reducing friction coefficients and wear between lubricated surfaces. The method includes providing an amount of an oil-soluble or oil-dispersible component selected from the group consisting of a photo-crosslinkable poly(2-cinnamoyloxyalkyl acrylate) core and a diblock acrylate copolymer corona in a fully formulated lubricant composition containing a base oil of lubricating viscosity. The lubricant composition containing the component is applied to a surface to be lubricated.

Abstract: An oil-soluble lubricating oil additive composition prepared by the process which comprises reacting a copolymer, with at least one polyether aromatic compound, and with at least one polyether aliphatic compound.

Abstract: Combinatorially generated peptides are provided that have binding affinity for polymethylmethacrylate (PMMA). The peptides may be used to deliver benefit agents to various PMMA surfaces.

Abstract: Hydraulic oil for use in construction machinery, wherein the hydraulic oil comprises a poly(meth)acrylate of weight average molecular weight in the range of from 30,000 to 100,000 in a highly refined base oil but does not incorporate an oiliness agent, and wherein the kinetic viscosity at 60° C. is in the range of from 25 to 60 mm{hacek over ( )}/s, the kinetic viscosity at 80° C. is in the range of from 15 to 34 mm{hacek over ( )}/s, the viscosity index is in the range of from 200 to 220, and the low temperature cranking viscosity at 25° C. is in the range of from 1000 to 8000 mPa·s. The hydraulic oil of the present invention not only has a high kinetic viscosity in the high-temperature domain even though the incorporation of an oiliness agent is omitted, and can thereby effect satisfactory operation efficiently and which has excellent braking characteristics, but which also has a low viscosity in the low-temperature domain and so has excellent low-temperature performance.